Herbs, annual, unbranched to much branched, 8--30 cm. Leaves spirally arranged; blade linear or linear-lanceolate to lanceolate-oblong, 1.5--7(--18) ´ 0.3--0.8 cm. Inflorescences terminal or terminal and axillary; cymes few-flowered, solitary or fascicled, long-pedunculate; bracteoles caducous, scars spaced less than 2 mm apart. Flowers bisexual, slightly bilaterally symmetric, 4--6 mm wide; sepals 2--3 mm; petals pinkish purple or violet, 3--3.5(--6) mm; fertile stamens 2; filaments bearded; staminodes 4. Capsules 2.5--5 mm. Seeds 2 per locule, deeply pitted, 1.3--1.8 mm. 2n = 20 (Trinidad).

Flowering summer--fall. Weed in lawns, gardens, and other open or lightly shaded, disturbed sites; introduced; Ala., Fla., Ga., La., N.C., S.C., Tex.; Central America; South America; native, Asia.

Murdannia nudiflora is found in the tropical areas of the Western Hemisphere.